Telephone-switchboard key.



K. WEMAN.

VTELEPHOM SWITGHBOARD KEY. APPLIOATION FILED MAR. l. 1909.

79,6 1 6. Patented Dec. 27, 1910.

W. 71; JJM Invenlvr. L e f' 4 n 4f 96k MR Wn- Jil-orneys.

KLAS WEMAN, OF BUFFALO, NEW YORK, ASSIGNOR TO ERICSSON MANUFACTURING COMPANY, 0F TONAWANDA, NEW YORK, A CORPORATION 0F NEW' YORK.

TELEPHONE-SWITCHBOARD KEY.

Specification of Letters Patent.

Patented Dec. 2'?, 1910.

Application filed March 1, 1909. Serial No. 480,744.

To all whom it may cof/wem:

Be it known that I, KLAS WEMAN, a citizen of the United States, residing at Buffalo, in the county of Erie and State of New York, have invented a new and useful Improvement in Telephone-Switchboard Keys, of which the following is a specication.

This invention relates to the keys of telephone switch boards.

One of its objects is to `improve the construction of the key with a view of minimizing the wear or friction between the keylever and the usual contact-springs.

Further objects are to simplify the construction of the key, and to improve the arrangement of the hanger or bracket which carries the spring-groups, so as to equalize the strain on opposite sides of the hanger and prevent loosening of the same.

In the accompanying drawings: Figure l is a front elevation of the key and the spring-groups. Figs. 2 and 3 are vertical sections on the correspondingly numbered lines in Fig. l, Fig. 2 showing the key-lever in its normal central position and Fig. 8 showing it tilted to one side. Fig. 4t is a perspective view of the key-lever. Fig. 5 is a view similar to Fig. 8, showing a` modilied construction of the key-lever.

Similar letters of reference indicate corresponding parts in the several views.

A indicates the usual escutcheon plate which is secured to the table of the switch board, not shown.

B indicates the hanger, frame or bracket secured to the escutcheon plate A and carrying the usual spring-groups. As shown, this hanger is preferably L-shaped or `in the form of an angle-plate and its short horizontal member Z) is secured to the underside of the escutcheon plate or equivalent support by screws 1.

In the example shown in the drawings, the spring-groups are arranged on opposite sides of the main vertical member of the hanger, and each group comprises a middle or main contact spring `C having the usual contact points c on opposite sides, and cooperating inner and outer contact springs C1, C2. These springs and their customary insulators are secured to the hanger by transverse bolts cl or other suitable fastenings. The inner springs are held out of contact with the metallic hanger by the usual rubber buttons e.

Each of the middle springs C is provided at its upper end with an anti-friction roller c1 of ivory, rubber or other insulating material,

Gr indicates the rocking disk of the key and g its handle. 'Ihe disk passes through the usual longitudinal slot z. of the escutchcon-plate, ,in which it is pivoted by a transverse pin c', preferably seated in a recess or bearing l formed in the upper side of the horizontal member Z) of the hanger, the pin being confined in said recess by the underside of the escutcheon plate.

At its lower end, in linewith its pivot, the key-lever is provided with a nose or tip g1 adapted to ride over one or the other pair of anti-friction rollers c1 when the keylever is tilted accordingly, thereby defiecting the corresponding middle springs out of Contact with the companion inner springs and ,into contact with the companion outer springs. In order to obtain a smooth and easy action of the key-lever, its tip is provided on opposite sides with inclined, downwardly-convergmg faces g2 which engage the rollers c1.

The tip g1 may be formed integrally with the key-lever, but for economy of construction, it is preferably made separate therefrom and its shank or contracted upper portion is soldered or otherwise secured in a transverse slot g3 formed centrally in the lower edge of the key-lever. Preferably the tip consists of two similar approximately V- shaped sections or halves stamped of sheet metal and placed face to face, as shown in the drawings.

The tip g1 extends laterally beyond the sides of the key-lever, by which construction the upper edge of the tip acts as a stop which limits the tilting` movement of the key-lever in both directions, by coming in contact with the underside of the horizontal hanger-flange b, as shown in Fig. 3. The hanger is provided in its top with a slot 7c for receiving the lower end of the key-lever and its tip.

As shown in the drawings, the main vertical mernber of the hanger is preferably located in line with the key-lever pivot z'. By thus locating the hanger and placing the spring-groups on opposite sides thereof, the deflecting strain upon the opposing sets of springs is equalized, thereby correspondingly equalizing the strain on the hanger and preventing springing and ultimate loosening of the same.

In the normal central position of the keylever shown in Figs. l and 2, the key-lever defiects none of the springs, permitting the middle springs C to make contact with the inner springs C1 and closing the corresponding circuits. Upon rocking the key-lever in either direction to the limit of its movement, its tip moves in the opposite direction and rides over the rollers 01 of the middle springs on the advancing side of the tip, thereby deflecting said springs outwardly out of contact with the corresponding inner springs C1 and into contact with the outer springs C2 and breaking and making the respective circuits accordingly. By the construct-ion shown in Figs. l to 4, the key-lever when turned in either direction and released, is returned to its central position by the deflected middle spring acting against the corresponding inclined face of the key-lever tip.

In the modified construction shown in Fig. 5, the key-lever tip g4 is provided in its front and rear faces with retaining grooves or seats g5 with which the rollers c1 interlock, for yieldingly retaining the key-lever in either of its extreme positions, avoiding the necessity of holding it in its tilted position by hand.

Obviously the tip may be provided with a single locking groove, if desired.

I claim as my invention:

l. In a telephone switch board key, the combination of a support, a key-lever pivoted thereto, an angle plate having its horizontal member secured to said support and its depending main member arranged substantially in line with the key-lever pivot, and groups of Contact springs secured to opposite sides of said depending member, a pair of the springs of said opposing groups being arranged on opposite sides of the keylever and adapted to be deflected outwardly by the same.

2. In a telephone Aswitch board key, the combination of a support, a key-lever pivoted thereto, an angle-plate having its horizent-al member secured to said support and its depending main member arranged substantially in line with the key-lever pivot, and groups of contact springs secured to opposite sides of said depending member, a pair of the springs of said opposing groups being arranged on opposite sides of the plunger and provided with anti-friction rollers, and the key-lever having a part arranged between said opposing rollers and adapted to engage either of the same.

3. In a telephone switch board key, the combination of coopera-ting contact springs, a key-lever having a slot, and a separate tip secured in said slot and adapted to engage said springs, said tip consisting of opposing approximately V-shaped halves or sections.

4. In a telephone switch board key, the

.combination of a slotted support, a hanger consisting of an angle plate having its upper horizontal member slotted lengthwise and secured to said support, spring groups secured to the vertical member of said hanger, a key-lever pivotally arranged in the slots of said support and said hanger and having a tip adapted to engage one or more of said springs, said tip extending` laterally beyond the key-lever and arranged to engage the underside ot said horizontal hanger-member.

Vit-ness my hand this 27 th day of February, 1909.

KLAS VEMAN. I/Vitnesses:

C. F. GEYER, E. GRAHAM. 

